The field of the present invention is the graphic arts. More particularly, the field comprises printing and reproducing an aesthetically pleasing print article and the process of making it.
Graphic artists appreciate that one way to enhance the appeal of a graphical image is to raise or lower certain portions of the image. By raising or lowering certain aspects of the image, ridges and valleys are created that not only interrupt the usually mundane flat surface of a graphical image, but allow the ridges and valleys to interact with light to create interesting and pleasing patterns. Raising a portion of the image above the normal surface is called "embossing" and creating a valley below the normal surface is called "etching". The process of embossing or etching an image not only requires two separate processes but is time consuming and expensive. For example, creating a typical embossed or etched sign required preparing stamps and dyes corresponding to the desired etches or embossed areas. Thus, creating an embossed or etched graphical image was a time consuming, difficult process that required special tools and skills.
It is well known in the art that aesthetically pleasing graphics enhance the quality of various articles including brochures, greeting cards, packaging material, trading cards, T-shirts and other articles that comprise a graphical image. In particular, several previous art patents exist that address improving the aesthetic qualities of signage, such as U.S. Pat. Nos. 3,912,842 and 5,762,379.
For example, U.S. Pat. No. 4,933,218 issued Jun. 12, 1990 shows a sign with a transparent substrate. The '218 patent discloses a process for creating the artificial appearance of an embossed or etched surface on a sign. To create this artificial appearance, a thick ridge of ink is deposited on the back side of a transparent substrate. This thick ridge of ink is disposed in the form of a desired design. A sheet made of paper, plastic or foil is carefully adhered behind the ink ridges and substrate. When an observer looks through the transparent substrate, the ink ridges thereby give a simulated appearance that the design has been etched or embossed on the sign.
Although the sign of the '218 patent artificially creates a visual impression of etching or embossing, the surface presented to an observer is still the flat, mundane substrate. Further, the process can be intricate and cumbersome as the sheet has a transparent adhesive on one side that requires careful handling. Further, the adhesive sheet has to be pressed carefully against the substrate and ink ridges. Applying this adhesive sheet requires the additional process of adhering, rolling or heating to sufficiently conform the sheet to the shape of the substrate and ridges. Additionally, although the sign of the '218 patent may contain color tinting, it does not allow for embossing or etching a complex image.
In U.S. Pat. No. 5,082,703, which was a continuation in part of the '218 patent, other substances are substituted for the adhesive sheet. For example, a silver or gold based solution can be sprayed behind the substrate and the ink ridges. Alternatively, dry reflective powder can be electroplated behind the substrate and the ink ridges. Although this provides alternative ways for providing a backing for the sign, it still entails an additional complicated process such as spraying or electroplating. Thus, the disadvantages of the previous art remained.
The U.S. Pat. No. 5,106,126 patent further attempted to create aesthetically pleasing signage by depositing an image in an ink layer on the back side of a transparent substrate and placing a reflective layer behind the image. Therefore, as an observer looks from the front through the plastic substrate, portions of the image appear reflective. However, the reflective layer is still difficult and expensive to apply. The reflective layer is preferably metalized mylar laminated to the image. Alternatively, the reflective layer can be a metallic paint or metallic ink sprayed or dipped behind the image. With the image and reflective material on the back side of the substrate, an observer still views the image by looking through the substrate. Therefore the surface presented to the observer is flat and not entirely interesting.
U.S. Pat. No. 5,223,357 is similar to the '126 patent in that an image is deposited on the backside of a transparent substrate and a reflective surface is placed behind the image. However, with the '357 patent the reflective surface is a holographic film. The holographic film is used to present variable color casts through the image, but the holographic film is expensive and has to be carefully secured to the substrate using an adhesive. Therefore, the process is expensive and resource consuming. Consistent with other previous art, the signage of the '357 patent suffers from being expensive and a flat, uninteresting effect for an observer.
Further, all the patents discussed above require a special and expensive substrate that is substantially transparent. Since the substrate must be transparent, none of the above patents can address the need to print aesthetically pleasing prints on an opaque surface. Opaque surfaces are ubiquitous in the graphic arts and include such everyday surfaces as cardboard, paper, cloth, Styrofoam, plastic sheeting, or other commonly used and inexpensive printable surfaces.
In viewing the signage discussed above, the observer looks through the substrate and views the image or pattern which is disposed on the back side of the substrate. With such a limitation, the images in the previous art can only be applied to one side of the substrate. However, for marketing and other purposes it is often desirable or efficient to print on both sides of a substrate. For example, packaging, greeting cards, trading cards, playing cards, bookcovers, and other such printed articles are enhanced by being printable on both sides of the substrate.
Thus, the previous art does not disclose an economical way to produce an aesthetically pleasing print article having a metallic surface and a tactile feel. Further, the previous art does not allow for this type of printing on two sides of an opaque substrate.